In reinforced concrete construction applications, such as highways, floors, or walls of buildings, spacer devices, commonly referred to as chairs, are required for supporting and maintaining reinforcing rods or bars which are positioned in the area where concrete is to be poured. These reinforcing rods are sometimes referred to as “rebars”. Depending on parameters, such as the total surface area and the thickness of the end product of concrete, reinforcement is mandated in varying degrees by building codes. One such method of reinforcement involves a steel mesh, while in major concrete construction, such as highways and high-rise buildings, reinforcing rods of various diameters, typically one-half inch or more, are required. In addition, on such jobs, the reinforcing bars may be positioned in spaced layers due to the thickness of the floor. In some installations, a first layer of rebar is provided, with the reinforcing rods or rebars in spaced parallel relationship, and generally parallel to the surface on which the concrete is to be poured. A second layer of rebar is then added, with the orientation of the second layer perpendicular to the first layer, thus forming a grid or lattice work. After the reinforcing bars or lattice work is prepared, the concrete is then poured over this grid or framework, which is ultimately embedded within the highway floor or wall.
For a concrete floor on a prepared surface, spacers or chairs are utilized for providing the vertical separation of the rebar grid from the surface on which the concrete is to be poured. The prepared surface may be a wood, plywood, or foam structure or a compacted surface, the latter of which my be provided with a layer of compacted sand, with a plastic sheet covering thereon providing a moisture barrier. Spacers or chairs are then positioned on the prepared surface for supporting the rebars in a plane generally parallel to the prepared surface. Typically, with modern building codes, a spacer is needed for every linear foot of the rebar.
With rebar spacers or chairs, one common problem is occasioned by the number of different sizes required to be maintained by a supplier to accommodate different thicknesses of poured concrete, such as two-inch, three-inch, four-inch, etc. and many intermediate fractional sizes. Another common problem with rebar spacers has been encountered in the method of securing the rebar to the chair or spacer, with twisted wire being the most common method. This particular problem is more acute when mutually perpendicular layers of rebar are coupled to the same chairs or spacers. With wire connections, a first strip of wire secures the first layer and a second strip of wire secures the perpendicular layer of rebar. With any metal or wire within the reinforcing bar grid work, there is a problem with rusting or decomposing of the wire or metal components.
Since the intersectional bar supports are used to support a large number of rebars in a desired spaced relationship above an underlying surface, industry standards have required that such intersectional reinforcing bar supports pass a “dragging” test. The purpose of the “dragging” test is to avoid any collapse of the mesh of rebars in the event that a dragging or displacement force is applied to the rebars. Since the mesh of rebars can have a very considerable weight, potential injury can occur if a pulling force is applied to the mesh of rebars and the mesh collapses onto the underlying surface. As such, the “dragging” test is applied by attaching a line to the mesh of rebars and pulling on the line to see if the reinforcing bar supports can withstand a fixed level of pulling force. As such, it is very important in the construction of such reinforcing bar supports to have a structure which strongly resists the dragging forces and avoids any potential collapse of the mesh rebar configuration.
When reinforcing bar supports are used to support a mesh of rebars above an underlying surface, it is very important to facilitate the flow of concrete in and around the mesh of rebars and in and around the reinforcing bar supports. If the reinforcing bar supports present too many obstacles to the flow of concrete, then voids in the concrete are possible. As such, it is very desirable to create such reinforcing bar supports which completely facilitate the flow of concrete while, at the same time, maintain the structural integrity of the bar support.
Since such reinforcing bar supports are relatively inexpensive items, it is important to be able to minimize the cost associated with the production of such reinforcing bar supports. Although the polymeric material used for the creation of such bar supports is relatively inexpensive, it is important to avoid unnecessary waste of the polymeric material. The cost of such polymers can add to the ultimate cost of the reinforcing bar support. It is important to be able to minimize the amount of polymer that is used for the creation of such bar supports while, at the same time, maintaining the strong structural integrity of such bar supports. Additionally, the minimization of the use of polymer in the formation of reinforcing bar supports will further minimize the costs associated with the transportation, delivery and storage of such reinforcing bar supports. By minimizing the weight associated with each of the bar supports, a larger number of bar supports can be transported to the construction site. Additionally, by minimizing the weight of the bar supports, the worker can more easily transport a relatively large number of bar supports to the desired location at the construction site. This further enhances the ability of the bar supports to minimize potential back injuries to the construction worker.
In the past, various patents have issued relating to these chair supports for reinforcing rods. In particular, the present inventor is the owner of U.S. Pat. Nos. 5,555,693 and 5,791,095 for such chairs. Each of these chairs has a receiving area with a horizontal section and a generally parabolic section extending transverse to the horizontal section. A plurality of separate legs extends downwardly from the receiving area. Each of the legs has a foot extending horizontally outwardly therefrom. The receiving area and the plurality of legs are integrally formed together of a polymeric material.
U.S. Pat. No. 3,788,025, issued on Jan. 29, 1974, to S. D. Holmes, describes a chair for supporting in right angular relation two reinforcing rods used in construction. The chair has a lower arched base part and an upper rod supporting part integral with the base. The base is an arched support with means for providing lateral, longitudinal, vertical support and strength. The rod supporting part comprises two spaced apart arms, the lower parts of which form a saddle for receiving one reinforcing rod and the upper part for each of which is formed by two separate spaced upstanding inwardly concave arms, the upper ends of which are spaced to provide an opening through which a second reinforcing rod, arranged at a right angle to the first rod, may be introduced.
U.S. Pat. No. 3,673,753, issued on Jul. 4, 1972, to G. C. Anderson, teaches a concrete reinforcing bar support in which a base supports an upright pedestal. A lower clamping portion is supported by the pedestal which has a first rod-receiving open passageway therethrough. Resilient detents extend from the lower clamping portion to retain a reinforcing rod disposed through the first passageway. An upper clamping portion is provided which includes a pair of hook members extending from the lower clamping portion. Each of the hook members has a mouth opening in the same direction to define a second rod-receiving passageway which is normally disposed to the first passageway.
U.S. Pat. No. 4,835,933, issued on Jun. 6, 1989, to F. P Yung, describes a spacer assembly which includes a spacer with a body having a base portion with a generally centrally disposed support post portion. One end of the support post portion is formed as a planar surface with a centrally located generally concave saddle portion configured for receiving a reinforcing bar. The planar surface is provided with apertures therethrough on both sides of the saddle. A clamp member is provided for simultaneously securing mutually perpendicular rebars to the chair. The clamp member is a generally U-shaped lower portion, with the depending arms thereof in spaced generally parallel relationship for engaging a first bar within the saddle. A generally identical pair of hook arms extends upwardly from the bight portion. The hook arms are oriented for engaging a second rebar in an orientation perpendicular to the first rebar engaged within the saddle portion.
U.S. Pat. No. 5,893,892, issued on Apr. 13, 1999, to Hardy, Jr. et al, teaches an apparatus for fixating and elevating an interconnected rebar lattice having individual longitudinal and transverse rebar intersections. The apparatus includes a holding portion having an open-ended recess with two opposing walls being generally U-shaped. The recess has longitudinal access and is sized and shaped to receive a longitudinal rod. An arc-shaped portion extends laterally outwardly from each opposing wall and perpendicular to the longitudinal access of the recess. The arc-shaped portion includes a recess and an opposing wall with each wall including a snap-type lock. A locking member has a generally arc-type portion and includes a snap-type lock for attaching to the arc-type portion and engaging with the snap-type lock of the arc-type portion. A leg portion extends downwardly from the holding portion and is integrally attached to a base.
U.S. Pat. No. 6,112,494, issued on Sep. 5, 2004, to Hardy, Jr. et al., teaches a system for affixing rebar lattice. The apparatus includes a holding portion having an open ended recess with two opposing walls being generally U-shaped. The recess has a longitudinal axis and is sized and shaped to receive a longitudinal rod. An arc-shaped portion extends lateral outwardly from each opposing wall and perpendicular to the longitudinal axis of the recess. The arc-shaped portion includes a recess and opposing walls including a snap-type lock. A locking member having a generally arc-shaped portion and includes a snap-type lock for attaching to the arc-shaped portions and engaging with the snap-type lock of the arc-shaped portions. A holding member is adapted to secure the individual longitudinal and transverse rebar intersections of the rebar lattice in a locking relationship while the leg portion holds the interconnected rebar lattice in a preselected elevated position.
The present inventor is the owner of several U.S. patents relating to such intersectional rebar chairs. For example U.S. Pat. No. 6,684,594, issued on Feb. 3, 2004, to the present inventor, describes a concrete reinforcing bar support having a base, a support structure extending upwardly from the base and a having a channel formed in an upper surface thereof, a first clamping structure affixed to the support structure on a side of the channel, and a second clamping structure affixed to the support structure on an opposite side of the channel. A first rebar extends through the channel. A second rebar is retained by the first and second clamping structures in a direction transverse to the first rebar. The retaining elements are provided on the clamping structures so as to engage the rebar when it is received within the second clamping structure. Lever elements extend outwardly from the clamping structure so as to provide a funneling type of structure so as to facilitate the introduction of the rebar into the second clamping structure.
U.S. Pat. No. 6,684,595, issued on Feb. 3, 2004, to the present inventor, teaches another type of intersectional reinforcing bar support. This bar support also includes a base, a support structure extending upwardly from the base and having a channel formed at an upper surface thereof, a first clamping structure affixed to the support structure on a side of the channel, and a second clamping structure affixed to the support structure on an opposite side of the channel. Each of the clamping structures has a curved element extending inwardly therefrom. A first rebar extends through the channel. A second rebar is retained by the first and second clamping structures in a direction transverse to the first rebar. A self adjusting retention mechanism is provided on a side of the second clamping structure opposite the curved surface so as to retain the rebar in a proper position therein.
U.S. Design Pat. No. D500,665, issued on Jan. 11, 2005, to the present inventor, teaches a unique design for such an intersectional rebar chair. A channel is formed at the top of the support structure. A pair of C-shaped clamping structures are located on opposite sides of the channel. The lipped element extends across the open face of the C-shaped members so as to facilitate the introduction of rebar into the interior of such C-shaped members.
U.S. application Ser. No. 11/234,756, from which the present application claims priority, describes an intersectional reinforcing bar support having a securing cap. In this reinforcing bar support, several holes are formed on the support structure. Although these holes facilitate the flow of concrete, it was found to be desirable to maximize through spaces formed in the support structure beyond those evidenced by the holes in the prior application. Additionally, in order to enhance the ability to pass a “dragging” test, it was felt desirable to expand the length dimension of the base such that the base extends for a greater distance than that of the channel which supports the transverse rebar. It was found that, under certain circumstances, it was not necessary to include the cap which extends over the clamping structures.
It is an object of the present invention to provide a bar support which is corrosion-proof.
It is another object of the present invention to provide a bar support adapted for use at intersections of rebars.
It is another object of the present invention to provide a bar support that can be placed on various flat surfaces.
It is another object of the present invention to provide a bar support that can be easily snap-fitted onto and locked around a reinforcing bar.
It is another object of the present invention to provide a bar support which allows a free flow of concrete therethrough.
It is a further object of the present invention to provide a bar support with a load-resistant stable support structure.
It is a further object of the present invention to provide a reinforcing bar support which is easy to use, easy to manufacture and relatively inexpensive.
It is another object of the present invention to provide a channel for such an intersectional chair which is suitably reinforcing so as to enhance the ability to retain the rebar within the channel.
It is still another object of the present invention to provide an intersectional chair which maximizes the ability to resist dragging forces applied to the mesh that is supported by the intersectional chair.
It is still a further object of the present invention to provide an intersectional chair which maximizes the structural integrity of the chair while minimizing the amount of polymer that is used in the formation of the chair.
These and other objects and advantages of the present invention will become apparent from the reading of the attached specification and appended claims.